It is known for starting the casting of a continuous casting system to tightly close off the lower mould opening before and during the casting start-up process with a dummy bar in order to prevent steel poured into the mould from flowing out. The dummy bar is introduced into the mould via the strand guide provided for the casting strand and which comprises the drive and guide rollers. The steel poured into the mould is partially solidified so that a strand with a solidified edge zone and a liquid core is produced. As soon as this edge zone is of a sufficient thickness, the dummy bar (and after the latter the hot strand, additional steel then being poured into the mould) is drawn out of the mould, once again by means of the strand guide.
The movement of the dummy bar is determined by the drive torque generated by the drive rollers and by the contact force and friction coefficients between the drive and guide rollers and the dummy bar. Interruptions, such as for example with a power failure, can lead to an uncontrollable movement of the dummy bar. This can lead to damage to the system, both when running in and when starting the casting.